Article Figures & Data
Figures
- Figure 1.
The distribution of the neural location (left) and general class of developmental process (right) of events used to develop the model, plotted against the event scale. The event scale, which is described in more detail in Figure 3, is a ranking of all these events on a scale from 0 to 1, and principally represents their order of occurrence across all of the species. New events added in this data analysis compared with the original model (Clancy et al., 2001) are in red and show not only the addition of late behavioral, physiological, and overall growth information to the model but also addition to the database throughout; events common to both in black.
- Figure 2.
Predicted developmental schedules for human (blue circle), macaque (red circle), cat (yellow circle), short-tailed opossum (green circle), and mouse (black circle), selected from the 18 species to illustrate the full range of developmental durations. In this graph the event scale is the x-axis, to which we have added a subset of the 271 events that were observed. This scale ranges from 0 to 1, but in this case, event scale numerical values are replaced by these example events. As will be described in Figure 3, the event scale is a common ordering of developmental events across all species. The y-axis is the estimated date of occurrence of each event in each species from conception (log scale). To determine when a particular event would be predicted to occur in any species from this graph, using the name of the event on the event scale, find where it intersects the regression line for that particular species. The y-axis value will be the predicted PC day for that event/species combination. In future graphical representations of the event scale, the event scale value for any named event can be found in Table 1. Also represented on this graph are interaction terms for corticogenesis and retinogenesis, with interaction terms always associated with individual species. The parallel lines for a subset of events in four of the species (black bordered circles for human, macaque, cat, and possum) represent delays in cortical neurogenesis with respect to their time of occurrence in the rodent and rabbit. In the cat, a second parallel line can be seen representing the delay of retinal neurogenesis (yellow circle with a black dot).
- Figure 3.
The relation of the event scale used in this analysis to the ordering of events that was used in the prior model. Plotted on the x-axis are the event scores determined by GLM as in Clancy et al. (2001), estimating values for all species-event combinations by determining their overall ranking, and fitting those scores on a scale from 0 to 1.5. The event scale of the present analysis plotted on the y-axis was derived by the quasi-Newton optimization method described in the text. The two values derived for each event are very highly correlated, and also conform to the necessary biological ordering of events (e.g., cell birth before cell death). Each of these two scales was designed to correlate perfectly, within its own dataset, with the estimated Y values for any rodent and rabbit species. This shows that the quasi-Newton optimization method essentially ranks the order of occurrence of events in development, but it differs in two important respects. First, it shows a statistically significant nonlinearity, most obvious in the higher values on each scale. Second, some events fall noticeably above the main regression line, the largest cluster are those to the left of the arrow on the figure, and may represent events in early axonogenesis and GABA-neuron generation, which are either very substantially shifted in their order between species or nonhomologous events.
- Figure 4.
Fit of empirical data to model values in four representative species. The x-axis is the predicted date of occurrence of all the events for which there were also empirical data points; the y-axis is the empirical value of the measured event in that species. As described in several technical aspects in the texts, the fit of predicted to actual days is very high.
- Figure 5.
Plotted are all of the empirically measured developmental events (y-axis) in the cat, versus predicted developmental time for each event (x-axis), before the fitting of a retinal neurogenesis interaction term. All of the events in retinal neurogenesis are highlighted by black circles and all other events are in gray. The retinal neurogenesis events all occur later than would be predicted by the general model for the cat. Consistent with the hypothesis that this developmental delay has occurred for the purpose of increasing the retinal cell populations associated with nocturnality, within the retinal neurogenesis group only retinal ganglion cells are delayed. Retinal ganglion cells are the only measured cell class in the cat retina that are neither rods nor have a connection with rods.
- Figure 6.
Phylogenetic tree plotting the positions of relative delay in cortical neurogenesis, to determine whether delay in onset of cortical neurogenesis, associated with a taxonomic grade shift up in neocortical volume, had occurred at single or multiple times in mammalian phylogeny. Bold pluses and minuses mark branches with delays described in this dataset, and which also have species with increased adult cortical volume, while the unmarked ones represent branches where only relative cortical volume differences in adults are known (Reep et al., 2007). Increases in relative cortical volume appear to have occurred at least three times in mammals, in Metatheria (various marsupials), in the branch giving rise to carnivores, various ungulates, and dolphins, and in primates. It cannot be determined from these data as yet whether a large cortex is the “basal” state, and reduced cortical volume has been selected for in glires, bats, shrews, and Afrotheria, or the reverse. Phylogeny from Song et al. (2012).
- Figure 7.
The maximum duration of neurogenesis across species, plotted on the basic segmental divisions of the embryonic vertebrate nervous system. Only one side of the neural plate is plotted, with the midline to the right, and more alar or lateral locations to the left. Rhombomeres 1–11, which give rise to the medulla, pons, and cerebellum, and the prosomeres, which give rise to the diencephalon and telencephalon, are indicated. The neural plate representation compresses the segmental divisions described previously (Garcia-Lopez et al. (2009) into four medial to lateral divisions. The latest date of neurogenesis observed in each division is plotted on the z-axis, as given by the mean of the species' event scores found there. Extended duration of neurogenesis is more likely in more alar (lateral) and more rostral divisions.
- Figure 8.
Comparison of the modeled relative rates of brain development for a metatherian (marsupial) and a eutherian (placental) mammal of similar adult brain sizes. The marsupial species is the Polyprodonta dunnart, the marsupial mouse, and the placental mammal is a rodent, the common mouse M. musculus. The x-axis is the event scale, and the y-axis shows the predicted PC day of the occurrence of each event in both species. In this graph, the y-axis is a linear, not a log scale, so that the differences in duration can be better appreciated in this case where brain sizes are comparable. The elevated points near the dunnart line represent the effect of the non-glires interaction term delaying cortical neurogenesis with respect to the mouse. The dunnart takes nearly twice as long to reach 80% of its adult brain size compared with the laboratory mouse, with later developmental events disproportionately protracted compared with early events.
- Figure 9.
The position of birth for six placental mammals relative to the event scale (x-axis); the age of each mammal in PC days can be read for birth (or any event scale value) on the y-axis. The five placental mammals are chosen to represent close to the full range of the dataset and include one highly precocial mammal, the guinea pig. For an example, in the mouse at birth cortical neurogenesis is still underway and synaptogenesis in the forebrain is only beginning, while in the guinea pig at birth, cortical neurogenesis, cortical cell migration, and basic axonogenesis is entirely complete, and the point of peak synaptic density has passed (human (blue dot), macaque (red dot), cat (yellow cat), guinea pig (green dot), and mouse (black dot).
- Figure 10.
The relationship of adult brain weight (x-axis, log scale), modeled slope (left), and intercept (right) values for all eutherian mammals. The slope of the modeled regression line (left) can be used as a measure of the number of days, and thus the total developmental duration required to reach the last maturational point measured is closely related to brain weight. The intercept (right), which gives the PC age when the first neurodevelopmental events occur, distinguishes precocial from altricial animals, and also relates to brain size. Of the rodents, for example, the precocial spiny mouse and guinea pig have the highest intercepts, while the altricial mouse and hamster have the lowest.
- Figure 11.
Top, Modeled regression slopes for two highly precocial rodents, the spiny mouse and guinea pig, compared with the altricial mouse (M. musculus) whose brain weight is similar to the spiny mouse, and the relatively altricial ferret, whose brain weight is close to the guinea pig; the regression slope for the macaque is also plotted. x-axis is the event scale, and the y-axis is predicted PC day (logged). Both precocial cases show the delayed onset of in utero neurodevelopment and very rapid progress through developmental stages characteristic of the precocial group. Elevated points associated with the ferret and macaque regression lines are the non-glires*corticogenesis interaction term. Bottom, Empirical data density and distribution, and fit of data to model, for the three most precocial species, the spiny mouse, guinea pig, and sheep. All modeled points are represented in gray, while the points for which there are empirical measurements are black circles.
Tables
- Table 1.
List of all events with corresponding event scores, sorted by location classification
Location Event score Location Event score Location Event score Brain stem Limbic system (continued) Cortex (continued) Cranial motor nuclei–peak 0.038 Presubiculum–peak 0.261 Neurogenesis cortical layer II/III–peak (VC) 0.395 Oculomotor nucleus cell generation–onset 0.041 Dentate gyrus–peak 0.264 Cortical axons reach dorsal lateral geniculate nucleus 0.396 Trigeminal mesencephalon nucleus–onset 0.041 Anterior commissure appears 0.267 Primary auditory cortex neurogenesis–offset 0.420 Trigeminal mesencephalon nucleus–offset 0.041 Ventromedial hypothalamus neurogenesis offset 0.269 Corticospinal tract decussates at the pyramids 0.428 Mesencephalic trigeminal cell generation–offset 0.042 Mitral cells–offset 0.274 Corticospinal tract reaches cervical spinal cord 0.439 Trigeminal motor nucleus–peak 0.051 Suprachiasmatic nucleus neurogenesis offset 0.283 Initial differentiation of layer V (S1) 0.444 Medial longitudinal fasciculus appears 0.062 CA1, CA2–peak 0.285 Cortical axons innervate dorsal lateral geniculate nucleus 0.465 Postproliferative zone in the medulla appears 0.073 Nucleus accumbens—peak 0.294 Neurogenesis cortical layer II/III–end (VC) 0.490 Trigeminal motor nucleus–offset 0.078 Tufted cells–peak 0.327 Range of rapid synaptogenesis (VC)–start 0.501 Superior colliculus generation–onset 0.079 Hippocampal commissure appears 0.337 Onset of barrels (S1) 0.504 Superficial superior colliculus laminae–start 0.095 Septal nuclei–offset 0.339 Corticospinal tract reaches dorsal horn of cervical spinal cord 0.514 Postproliferative zone appears in the tegmentum 0.112 Olfactory tubercle generation–offset 0.362 Onset of decrease in fractional anisotropy 0.515 Posterior commissure appears 0.112 Entorhinal cortex neurogenesis offset 0.375 Onset of sublayers in layer V (S1) 0.517 Lateral cuneate nucleus–onset 0.119 Hippocampal CA3 neurogenesis offset 0.380 Onset of trilaminar plate (S1) 0.517 Lateral and medial superior olivary nucleus–onset 0.119 Hippocampal CA1 neurogenesis offset 0.387 Adult-like cortical innervation of dorsal lateral geniculate nucleus 0.531 Cranial sensory nuclei–peak 0.120 Subicular cortex neurogenesis offset 0.389 Onset of barrel field septa (S1) 0.555 Postproliferative zone appears in the pretectum 0.125 Granule cells in the dentate gyrus–peak 0.583 Visual cortical axons in SC 0.570 Medial cuneate nucleus–peak 0.135 Olfactory tract myelination onset 0.634 Corticospinal projections reach lumbar levels 0.583 Reticular nuclei—peak 0.155 Stria medullaris myelination onset 0.653 First cortical visually evoked potentials 0.590 Postproliferative zone appears in the superior colliculus 0.157 Fornix myelination onset 0.675 Corticospinal tract reaches the sacral region 0.623 Inferior colliculus generation–onset 0.171 Anterior commissure myelination onset 0.677 Middle cerebellar peduncle myelination onset 0.652 Lateral cuneate nucleus–peak 0.186 Mammillothalamic tract myelination onset 0.689 External capsule myelination onset 0.666 Substantia nigra–peak 0.187 Hippocampus myelination onset 0.699 Cingulum myelination onset 0.687 Sensory nucleus of the trigeminal nerve–offset 0.199 Fasciculus retroflexus myelination onset 0.700 Internal capsule myelination onset 0.692 Lateral and medial superior olivary nucleus–offset 0.199 Stria terminalis myelination onset 0.703 Corpus callosum body myelination onset 0.722 Superior colliculus–peak 0.202 Splenium myelination onset 0.732 Inferior colliculus–peak 0.203 Thalamus Plasticity/OD critical period–start 0.770 Raphe nucleus neurogenesis–offset 0.206 Medial geniculate nucleus onset 0.113 Range of rapid synaptogenesis (VC)–end 0.849 Medial cuneate nucleus–offset 0.249 Dorsal lateral geniculate nucleus–start 0.127 Visual cortex peak synaptic density (area 17) 0.869 Pontine nuclei–peak 0.255 Postproliferative zone appears in thalamus 0.144 Prefrontal cortex peak synaptic density 0.886 Lateral cuneate nucleus–offset 0.262 Medial geniculate nucleus–peak 0.176 Plasticity/OD critical period–end 0.901 Superficial superior colliculus laminae–offset 0.279 Ventral lateral geniculate nucleus–peak 0.177 Corpus callosum body myelination end 0.971 Superior colliculus generation–offset 0.308 Dorsal lateral geniculate nucleus–peak 0.183 Middle cerebellar peduncle myelination end 1.000 Dopaminergic axons from midbrain reach subplate 0.352 Ventroposterior and ventrobasal nuclei - peak 0.191 Inferior colliculus generation–offset 0.381 Ventrobasal neurogenesis - onset 0.194 Whole brain Dopaminergic axons from midbrain reach cortical plate 0.395 Medial geniculate nucleus offset 0.211 20% maximum brain weight (day) 0.586 Dopaminergic axons from midbrain in cerebral cortex 0.499 Dorsal lateral geniculate nucleus–end 0.228 30% maximum brain weight (day) 0.635 Superficial superior colliculus–start of lamination 0.504 Anteroventral, anteromedial, anterodorsal nuclei–peak 0.238 40% maximum brain weight (day) 0.682 Inferior cerebellar peduncle myelination onset 0.543 Lateral geniculate nucleus axons in subplate 0.305 50% maximum brain weight (day) 0.729 Superior colliculus segregation 0.548 ventrobasal neurogenesis–offset 0.341 60% maximum brain weight (day) 0.788 Ipsi/contra segregation in superior colliculus 0.561 Pulvinar projections in interior zone of prestriate isocortex 0.375 70% maximum brain weight (day) 0.858 Medial lemniscus myelination onset 0.564 Pulvinar projections in subplate of prestriate isocortex 0.471 80% maximum brain weight (day) 0.949 Posterior commissure myelination onset 0.591 Pulvinar projections in cortical plate of prestriate isocortex 0.515 Onset of synapse elimination in neurons of the soleus 0.629 Lateral geniculate nucleus axons in cortical layer IV 0.545 Whole organism Brachium inferior colliculus myelination onset 0.664 Ipsi/contra segregation in lateral geniculate nucleus 0.561 Surface righting onset 0.573 Optic radiation myelination onset 0.652 Rooting reflex offset 0.623 Cerebellum Auditory radiation myelination onset 0.668 Auditory startle reaction 0.648 Inferior olive generation–onset 0.058 Lateral geniculate nucleus myelination onset 0.680 Preyer reflex 0.681 Inferior olivary nucleus–peak 0.092 Vibrissa placing adult like pattern 0.695 Purkinje cell generation–onset 0.110 Air righting reflex 0.730 Cerebellum (continued) Striatum Whole organism (continued) Postproliferative zone appears in the cerebellum 0.125 Ganglionic eminence postproliferative zone appears 0.088 Semi-adult-like sleep cycle 0.745 Inferior olive generation–offset 0.137 Caudatoputamen generation–onset 0.131 Visual placing is mature 0.768 Purkinje cells–peak 0.142 Globus pallidus–peak 0.140 Postconception walking onset 0.794 Deep cerebellar nuclei–peak 0.151 Claustrum–peak 0.147 Anteroventral cochlear nucleus–peak 0.179 Caudatoputamen–peak 0.186 Sensory periphery Purkinje cell generation offset 0.200 Claustrum offset 0.308 Trigeminal ganglion cell generation–onset 0.000 Cochlear nuclei–peak 0.220 Caudatoputamen–offset 0.519 Trigeminal ganglion cell generation–offset 0.195 Superior cerebellar peduncle myelination onset 0.564 Lateral lemniscus myelination onset 0.572 Ears open 0.668 Lenticular fasciculus myelination onset 0.602 Limbic system Striatum myelination onset 0.715 Retina Locus ceruleus–onset 0.041 Photoreceptor generation–onset 0.054 Locus ceruleus–peak 0.059 Cortex Horizontal cell generation–onset 0.059 Magnocellular basal forebrain–peak 0.071 Subplate—peak 0.071 Retinal ganglion cell generation–start 0.091 Mitral cells onset 0.085 Subplate–onset of neurogenesis 0.072 Retinal horizontal cells–peak 0.153 Olfactory tubercle generation–onset 0.093 Neurogenesis cortical layer VI–start (VC) 0.117 Amacrine generation onset 0.158 White matter appears in the hypothalamus 0.097 Cortical plate first observed/visible 0.123 axons in optic stalk 0.163 Preoptic nucleus generation–onset 0.102 Primary auditory cortex neurogenesis–onset 0.136 Retinal ganglion cells–peak 0.195 Septal nuclei–onset 0.110 Cortical subventricular zone–onset 0.164 Optic axons at chiasm of optic tract 0.198 Locus ceruleus–offset 0.113 Primary somatosensory cortex–layer VI offset 0.194 Rapid axon generation in optic nerve–start 0.217 Entorhinal cortex neurogenesis onset 0.119 Neurogenesis cortical layer V–start (VC) 0.203 Cones–peak 0.264 Raphe complex–peak 0.120 Neurogenesis cortical layer VI–peak (VC) 0.204 Optic axons invade visual centers 0.270 Medial forebrain bundle appears 0.125 Neocortical layer I emerges 0.207 Rod generation–onset 0.282 Hippocampal CA3 neurogenesis onset 0.139 GABA cells in subplate–start 0.213 Muller cell generation–onset 0.282 Subicular cortex neurogenesis onset 0.139 External capsule appears 0.215 Retinal amacrine cells–peak 0.298 Granule cell layer fascia dentata neurogenesis onset 0.140 Primary somatosensory cortex–layer V offset 0.220 Bipolar cell generation–start 0.300 Hippocampal CA1 neurogenesis onset 0.143 Internal capsule appears 0.236 Optic axons reach dorsal lateral geniculate nucleus and superior colliculus 0.319 Granule cells in the dentate gyrus–onset 0.150 Lhx6 first in cortex in GABAergic cells 0.238 Retinal ganglion cell generation–end 0.333 Postproliferative zone appears in the medial pallium 0.151 GABA cells in subplate–end 0.249 Horizontal cell generation–offset 0.371 Mammillothalamic tract appears 0.153 Primary somatosensory cortex–layer 2/3 onset 0.255 Optic nerve axon number–peak 0.392 Preoptic nucleus–peak 0.157 Neurogenesis cortical lamina VI–end (VC) 0.258 Onset of retinal waves stage II 0.401 Fasciculus retroflexus appears 0.162 Neurogenesis cortical lamina IV–start (VC) 0.267 Onset of retinal waves stage I 0.425 Stria medullaris thalami appears 0.166 Neurogenesis cortical layer V–peak (VC) 0.268 Rods–peak 0.464 Supraoptic nucleus of hypothalamus offset 0.169 Primary somatosensory cortex–layer IV offset 0.283 Retinal bipolar cells—peak 0.478 Suprachiasmatic nucleus–peak 0.170 GABA-ir cells in lower intermediate zone 0.286 End of retinal waves stage I 0.520 Amygdala–peak 0.177 GABA positive cells appear in lower intermediate zone 0.287 Bipolar cells generation–offset 0.541 Mitral cells–peak 0.182 Peak subventricular zone expansion in the developing isocortex 0.289 Amacrine cell generation–offset 0.552 Endopiriform neurogenesis offset 0.193 Subplate and intermediate zone apoptosis onset 0.302 Rod generation—offset 0.561 Anterior olfactory nucleus–peak 0.194 Neurogenesis cortical layer V–end (VC) 0.305 Onset of retinal waves stage III 0.573 Nucleus of lateral olfactory tract–peak 0.198 Neurogenesis cortical layer IV–peak (VC) 0.320 Retinal waves 0.575 Septal nuclei–peak 0.215 Cortical plate apoptosis onset 0.321 End of retinal waves stage II 0.578 Entorhinal cortex–peak 0.230 Neurogenesis cortical layer II/III–start (VC) 0.342 Rapid axon loss in optic nerve ends 0.583 Olfactory tubercle generation–peak 0.238 Corpus callosum appears 0.359 Muller cell generation–offset 0.597 Fornix appears 0.241 Neurogenesis cortical layer IV–end (VC) 0.362 Optic tract myelination onset 0.597 Stria terminalis appears 0.243 Layer IV genesis–start 0.366 Eye opening 0.663 Subiculum–peak 0.248 Primary somatosensory cortex–layer 2/3 offset 0.368 First electroretinogram 0.665 Parasubiculum–peak 0.252 Cortical axons reach thalamus 0.371 End of retinal waves stage III 0.672 Optic tract myelination end 0.847 Within location subcategories, events are listed from lowest to highest event score.
Species Constant Slope Precocial score Adult brain weight (g) Adult male body weight (g) Gestational length (days) Spiny mouse 2.82 0.622 1.356 0.7 42 39 Guinea pig 2.904 1.573 0.841 4 640 68.5 Hamster 2.189 1.644 0.336 1.12 108 15.5 Rat 2.31 1.705 0.445 2 207 21 Gerbil 2.532 1.715 0.401 1.02 70 25 Mouse 2.145 1.894 0.408 0.45 18 18.5 Rabbit 2.382 1.959 0.537 9.6 2170 31 Ferret 2.706 2.174 0.463 7.1 1900 41 Cat 2.784 2.28 0.61 28.4 4000 65 Macaque 3.27 2.413 0.761 93.8 5340 165 Short-tailed opossum 2.261 2.508 0.717 8 105 13.5 Dunnart 2.576 2.508 0.612 0.3 32 13.5 Wallaby 3.141 2.508 0.949 20 115 29.3 Quoll 2.759 2.508 0.65 3.38 650 18 Brush-tailed opossum 2.793 2.508 0.871 9.4 3150 17.5 Quokka 3.03 2.508 0.884 13.9 2700 27 Sheep 2.909 2.533 0.822 160 45000 147 Human 3.167 3.72 0.654 1350 70000 270 Included data are species constant, precocial score, adult brain and body weight, and gestational length for each species.
- Table 3.
List of location and process classifications with brief descriptions of each. All locations are determined by the starting area of the phenomenon that is observed
Description Location Brain stem Encompasses the spinal cord, medulla, and mesencephalon Cerebellum The presumptive cerebellum Limbic system Amygdala, hippocampus, septum, olfactory bulbs, olfactory, subicular, and entorhinal cortex Thalamus All thalamic nuclei Striatum Globus pallidus, caudate nucleus Cortex Isocortex Whole brain Gross brain growth Whole organism Behavioral events Sensory periphery Peripheral nervous system Retina Retina, retinal ganglion cells Process Description Neurogenesis Cell cycle exit for any group of cells Axon extension When axons arrive at targets, form synapses, axon growth Segregation Differentiation of a population of cells GABA cortex GABAergic cells that have origins in the striatum or isocortex Subtractive event Cell death Retinal waves Patterns of developing retinal activity Synapse Elimination Decrease in synapse numbers Sensorimotor Behavioral or reflexive event Brain growth Gross brain development Myelination First wrap of a glial cell around a neuron Electrophysiology Onset of electrical activity Process Rat Mouse Human Gerbil Short-tailed opossum Dunnart Macaque Wallaby Quoll Brush-tailed opossum Quokka Hamster Spiny mouse Guinea pig Rabbit Sheep Ferret Cat Neurogenesis 0.06 0.07 0.14 0.11 0.10 0.11 0.09 0.09 0.10 0.09 0.10 0.06 0.04 0.10 0.08 0.10 0.08 0.08 Axon extension 0.05 0.06 0.11 0.09 0.09 0.09 0.07 0.08 0.08 0.08 0.08 0.05 0.04 0.08 0.06 0.08 0.07 0.07 Segregation 0.05 0.06 0.11 0.08 0.09 0.09 0.07 0.08 0.08 0.08 0.08 0.05 0.06 0.06 0.06 0.08 0.07 0.07 GABA cortex 0.06 0.07 0.14 0.11 0.10 0.11 0.09 0.10 0.10 0.10 0.10 0.06 0.03 0.09 0.08 0.10 0.08 0.08 Subtractive event 0.05 0.06 0.11 0.08 0.08 0.09 0.07 0.08 0.08 0.08 0.08 0.05 0.05 0.07 0.06 0.08 0.07 0.07 Retinal waves 0.06 0.06 0.12 0.08 0.09 0.10 0.08 0.09 0.09 0.09 0.09 0.06 0.07 0.06 0.07 0.09 0.08 0.08 Synapse Elimination 0.05 0.06 0.11 0.07 0.10 0.10 0.08 0.09 0.10 0.09 0.10 0.07 0.10 0.07 0.07 0.09 0.08 0.07 Sensorimotor 0.06 0.06 0.12 0.07 0.10 0.10 0.08 0.09 0.10 0.09 0.10 0.07 0.10 0.06 0.08 0.09 0.08 0.08 Brain growth 0.04 0.05 0.09 0.06 0.08 0.09 0.06 0.08 0.08 0.08 0.08 0.06 0.11 0.05 0.07 0.07 0.07 0.06 Myelination 0.05 0.06 0.10 0.06 0.09 0.10 0.07 0.09 0.09 0.09 0.09 0.06 0.10 0.06 0.07 0.08 0.07 0.07 Electrophysiology 0.05 0.06 0.11 0.06 0.09 0.10 0.07 0.09 0.09 0.09 0.09 0.06 0.09 0.06 0.07 0.08 0.07 0.07
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